Sodicity in irrigated soils in Saskatchewan: Chemistry and structural stability

1995 ◽  
Vol 75 (2) ◽  
pp. 177-185 ◽  
Author(s):  
D. Curtin ◽  
H. Steppuhn ◽  
F. Selles ◽  
A. R. Mermut
Keyword(s):  
Structural Damage ◽  
Colloidal Particles ◽  
Water Extract ◽  
Structural Deterioration ◽  
Extractable P ◽  
Soil Water Extract ◽  
Chemical Conditions ◽  
High Level ◽  
Water Extractable ◽  
Irrigated Soils

Irrigation with sodic waters may damage soil structure, but neither the processes involved nor the critical levels of exchangeable Na have been well defined for prairie soils. We examined two irrigated soils from southern Saskatchewan on which sodicity damage had occurred to determine the processes and the chemical conditions (exchangeable Na and electrolyte concentration) that cause structural damage. Dispersion of clays in the upper 20 cm of the profile seemed to be the primary cause of structural deterioration. Examination of irrigated soil by scanning electron microscopy (SEM) showed that sand- and silt-size grains were stripped of binding colloidal particles and that large pore spaces had formed, creating very loose aggregates. In one of the soils, physical instability was observed at an exchangeable-Na percentage (ESP) of only about 10%, indicating that some soils in Saskatchewan are relatively sensitive to sodicity. With a 1:5 (wt vol−1) soil/water extract, the electrical conductivity (EC) needed to prevent clay dispersion when soil suspensions were mechanically agitated was about 0.2 dS m−1 in the absence of Na, increasing to 1.5–2 dS m−1 at a sodium adsorption ratio of 20 (mmolc L−1)0.5. Sodic conditions greatly altered soil chemical behavior, with the most sodic soil having an extremely high level of water-extractable P. In a laboratory experiment, addition of Ca (as CaCl2 or gypsum) to replace Na reduced water-extractable P from 78 mg kg−1 to less than 20 mg kg−1. The effect of sodicity on P solubility was likely due to a decrease in surface electrostatic potential as exchangeable Na increased. Increased solubility of P along with the potential for runoff and erosion from Na-affected soils could result in increased inputs of P to surface waters. Key words: Sodicity hazard, clay disperson, phosphate solubility

Leaching of dissolved phosphorus from tile-drained agricultural areas

2016 ◽  
Vol 73 (12) ◽  
pp. 2953-2958 ◽  
Author(s):  
H. E. Andersen ◽  
J. Windolf ◽  
B. Kronvang
Keyword(s):  
Soil Layer ◽  
High Concentration ◽  
Measured Concentration ◽  
Leaching Potential ◽  
Dissolved Phosphorus ◽  
Olsen P ◽  
P Loss ◽  
Tile Drains ◽  
Extractable P ◽  
Water Extractable

Abstract We investigated leaching of dissolved phosphorus (P) from 45 tile-drains representing animal husbandry farms in all regions of Denmark. Leaching of P via tile-drains exhibits a high degree of spatial heterogeneity with a low concentration in the majority of tile-drains and few tile-drains (15% in our investigation) having high to very high concentration of dissolved P. The share of dissolved organic P (DOP) was high (up to 96%). Leaching of DOP has hitherto been a somewhat overlooked P loss pathway in Danish soils and the mechanisms of mobilization and transport of DOP needs more investigation. We found a high correlation between Olsen-P and water extractable P. Water extractable P is regarded as an indicator of risk of loss of dissolved P. Our findings indicate that Olsen-P, which is measured routinely in Danish agricultural soils, may be a useful proxy for the P leaching potential of soils. However, we found no straight-forward correlation between leaching potential of the top soil layer (expressed as either degree of P saturation, Olsen-P or water extractable P) and the measured concentration of dissolved P in the tile-drain. This underlines that not only the source of P but also the P loss pathway must be taken into account when evaluating the risk of P loss.

scholarly journals Exploration of CRISPR/Cas9-based gene editing as therapy for osteoarthritis

2019 ◽  
Vol 78 (5) ◽  
pp. 676-682 ◽  
Author(s):  
Lan Zhao ◽  
Jian Huang ◽  
Yunshan Fan ◽  
Jun Li ◽  
Tianming You ◽  
...  
Keyword(s):  
Structural Damage ◽  
Drug Targets ◽  
Gene Editing ◽  
Joint Damage ◽  
Loss Of Function ◽  
Adeno Associated Virus ◽  
Structural Deterioration ◽  
Efficient Gene ◽  
Genes Encoding ◽  
Surgically Induced

ObjectivesOsteoarthritis (OA) is a painful and debilitating disease and it is associated with aberrant upregulation of multiple factors, including matrix metalloproteinase 13 (MMP13), interleukin-1β (IL-1β) and nerve growth factor (NGF). In this study, we aimed to use the CRISPR/Cas9 technology, a highly efficient gene-editing tool, to study whether the ablation of OA-associated genes has OA-modifying effects.MethodsWe performed intra-articular injection of adeno-associated virus, which expressed CRISPR/Cas9 components to target each of the genes encoding MMP13, IL-1β and NGF, in a surgically induced OA mouse model. We also tested triple ablations of NGF, MMP13 and IL-1β.ResultsLoss-of-function of NGF palliates pain but worsens joint damage in the surgically induced OA model. Ablation of MMP13 or IL-1β reduces the expression of cartilage-degrading enzymes and attenuates structural deterioration. Targeting both MMP13 and IL-1β significantly mitigates the adverse effects of NGF blockade on the joints.ConclusionsCRISPR-mediated ablation of NGF alleviates OA pain, and deletion of MMP13-1β or IL-1β attenuates structural damage in a post-traumatic OA model. Multiplex ablations of NGF, MMP13 and IL-1β provide benefits on both pain management and joint structure maintenance. Our results suggest that CRISPR-based gene editing is useful for the identification of promising drug targets and the development of feasible therapeutic strategies for OA treatment.

Phosphorus effects on competitive interactions of smooth pigweed (Amaranthus hybridus) and common purslane (Portulaca oleracea) with lettuce (Lactuca sativa)

Weed Science ◽  
1998 ◽  
Vol 46 (3) ◽  
pp. 307-312 ◽  
Author(s):  
Bielinski M. Santos ◽  
Joan A. Dusky ◽  
William M. Stall ◽  
Donn G. Shilling ◽  
Thomas A. Bewick
Keyword(s):  
Competitive Ability ◽  
Organic Soils ◽  
Weed Species ◽  
Population Densities ◽  
Replacement Series ◽  
Amaranthus Hybridus ◽  
Extractable P ◽  
Common Purslane ◽  
Smooth Pigweed ◽  
Water Extractable

Replacement series studies were conducted under controlled conditions to determine the effect of phosphorus (P) rates and population densities on the competitiveness of smooth pigweed and common purslane with lettuce. Densities were 2, 4, and 8 plants per 113 cm2, whereas P rates were 0, 0.4, and 0.8 g PL−1soil. A P-deficient Histosol (0.3 mg water-extractable P L−1soil) was used. High P fertility enhanced the competitive ability of lettuce in smooth pigweed-lettuce mixtures. Smooth pigweed was not responsive to P rates. However, luxurious P consumption by smooth pigweed occurred, reducing the amount of the nutrient available for lettuce absorption. In common purslane-lettuce mixtures, the weed was responsive to P rates, increasing its competitive ability, whereas no increase in lettuce competitive ability was observed. Both weed species were more competitive than lettuce. Competition for P appears to be the main mechanism of common purslane interference on lettuce grown in low-P organic soils. Alternative fertilization strategies (i.e., banded applications) may reduce the effect of smooth pigweed on lettuce.

A laboratory study of phosphorus mobilisation from commercial fertilisers

Soil Research ◽  
2003 ◽  
Vol 41 (6) ◽  
pp. 1201 ◽  
Author(s):  
D. Nash ◽  
M. Hannah ◽  
L. Clemow ◽  
D. Halliwell ◽  
B. Webb ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Total Variation ◽  
Laboratory Study ◽  
High Moisture ◽  
Single Superphosphate ◽  
South Eastern ◽  
Extractable P ◽  
Eastern Australia ◽  
Water Extractable ◽  
South Eastern Australia

Phosphorus (P) exported from pastures following fertiliser application contributes to the nutrients and associated problems in the streams and rivers of south-eastern Australia. This laboratory study examined whether attributes of P fertilisers may affect P exports soon after their application to field soils; 3 commercial fertilisers [diammonium phosphate (DAP), single superphosphate (SSP), and sulfur-coated single superphosphate (CSSP)] were applied to 2 repacked soils (Arawata and Ellinbank) at 5 moisture contents.Soil type was the most important factor affecting water-extractable P (expressed as a percentage of the P added as fertiliser), accounting for 30% of the total variation. The majority of this variation is explained by the water-extractable P concentrations in the Arawata low moisture treatments. These treatments [7, 6, and 6% soil moisture when equilibrated at 99, 95, and 86.5% relative humidity (RH), respectively] contained water-extractable P concentrations c. 3 times higher than the high moisture (c. 20 and 25% soil moisture) or the Ellinbank treatments. This result probably reflects differences in soil properties including the extent of water repellency and P adsorption.Fertiliser type explained only 6.9% (P < 0.001) of the total variation in water-extractable P, partially as a result of the 86.5% RH (a low moisture) Arawata treatment. In this Arawata low moisture treatment, the mean extractable P was similar for both DAP and SSP, 13.1% [least significant interval (l.s.i.) 16.7–10.3] and 11.3% (l.s.i. 14.3–8.9), respectively, but for SSP, water-extractable P increased over time unlike any other treatment. Water-extractable P from DAP was approximately double that from SSP for the Ellinbank and high moisture treatments. The higher water-extractable P following DAP application is explained in terms of its chemical properties and reaction products. Sulfur coating the SSP granules (CSSP) increased water-extractable P, as did higher soil moisture.This study suggests that under conditions present in most pastures in south-eastern Australia and depending on soil hydrology, water-extractable P and P export from fertilisers may increase in the order DAP > CSSP > SSP if overland flow occurs soon after their application.

A comparison of some surface soil phosphorus tests that could be used to assess P export potential

Soil Research ◽  
2007 ◽  
Vol 45 (5) ◽  
pp. 397 ◽  
Author(s):  
David Nash ◽  
Murray Hannah ◽  
Kirsten Barlow ◽  
Fiona Robertson ◽  
Nicole Mathers ◽  
...  
Keyword(s):  
Organic P ◽  
Soil Tests ◽  
Soil P ◽  
Olsen P ◽  
P Sorption ◽  
P Loss ◽  
Extractable P ◽  
Soil P Tests ◽  
Total P ◽  
Water Extractable

Phosphorus (P) exports from agricultural land are a problem world-wide and soil tests are often used to identify high risk areas. A recent study investigated changes in soil (0–20 mm), soil water and overland flow in 4 recently laser-graded (<1 year) and 4 established (laser-graded >10 years) irrigated pastures in south-eastern Australia before and after 3 years of irrigated dairy production. We use the results from that study to briefly examine the relationships between a series of ‘agronomic’ (Olsen P, Colwell P), environmental (water-extractable P, calcium chloride extractable P, P sorption saturation, and P sorption), and other (total P, organic P) soil P tests. Of the 2 ‘agronomic’ soil P tests, Colwell P explained 91% of the variation in Olsen P, and Colwell P was better correlated with the other soil tests. With the exception of P sorption, all soil P tests explained 57% or more of the total variation in Colwell P, while they explained 61% or less of Olsen P possibly due to the importance of organic P in this soil. Variations in total P were best explained by the organic P (85%), Calcium chloride extractable P (83%), water-extractable P (78%), and P sorption saturation (76%). None of the tests adequately predicted the variation in P sorption at 5 mg P/L equilibrating solution concentration. The results of this limited study highlight the variability between soil P tests that may be used to estimate P loss potential. Moreover, these results suggest that empirical relationships between specific soil P tests and P export potential will have limited resolution where different soil tests are used, as the errors in the relationship between soil test P and P loss potential are compounded by between test variation. We conclude that broader study is needed to determine the relationships between soil P tests for Australian soils, and based on that study a standard protocol for assessing the potential for P loss should be developed.

scholarly journals A Feasibility Study of the Drive-By Method for Damage Detection in Railway Bridges

2019 ◽  
Vol 9 (1) ◽  
pp. 160 ◽  
Author(s):  
Marco Carnevale ◽  
Andrea Collina ◽  
Tim Peirlinck
Keyword(s):  
Structural Damage ◽  
Damage Identification ◽  
Train Track ◽  
Operational Parameters ◽  
Railway Bridges ◽  
Acceleration Sensors ◽  
Magnetic Inspection ◽  
Track Irregularity ◽  
High Level ◽  
Track Bridge

Damage identification and localization in railway bridges is a widely studied topic. Strain, displacement, or acceleration sensors installed on the bridge structure are normally used to detect changes in the global behavior of the structure, whereas approaches like ultra-sonic testing, acoustic emission, and magnetic inspection are used to check a small portion of structure near localized damage. The aim of this paper is to explore another perspective for monitoring the structural status of railway bridges, i.e., to detect structural damage from the dynamic response of the train transiting the bridge. This approach can successfully be implemented in the case of resonant bridges, thanks to the high level of acceleration generated, but its application becomes more challenging when the excitation frequencies due to train passage do not excite the first mode of vibration of the bridge. The paper investigates the feasibility of the method in the latter case, through numerical simulations of the complete train-track-bridge system. Accelerations on axleboxes and bogies are processed through suitable algorithms to detect differences arising when the train crosses a defective bridge or a healthy one. The results outline the main operational parameters affecting the method, the best placement for sensors, and the best frequency range to be considered in the signal processing, also addressing the issues that are related to track irregularity. Good performance can be achieved in the case of short bridges, but a few practical issues must be tackled before the method could be tested in practice.

Dose-Dependence of Pb-Ion Implantation Damage in Zirconolite, Hollandite, and Zircon

1981 ◽  
Vol 11 ◽  
Author(s):  
T. J. Headley ◽  
G. W. Arnold ◽  
C. J. M. Northrup
Keyword(s):  
Radiation Damage ◽  
Structural Damage ◽  
Accelerated Aging ◽  
Dose Dependence ◽  
High Level Waste ◽  
Long Term Stability ◽  
Waste Forms ◽  
Recent Approach ◽  
High Level

The long-term stability of nuclear waste forms is an important consideration in their selection for safe disposal of radioactive waste. Stability against long-term radiation damage is particularly difficult to assess by short-term laboratory experiments. Much of the displacement damage in high-level waste forms will be generated by heavy recoil nuclei emitted during the α-decay process of long-lived actinide elements. Hence, an accelerated aging test which reliably simulates the α-recoil damage accumulated during thousands of years of storage is desirable. One recent approach to this simulation is to implant the waste form with heavy Pb-ions.I- 6 If the validity of this approach is to be fully assessed, two important questions which have not yet been investigated must be answered.(1) Is the structural damage, including cumulative effects, similar for irradiation by Pb-ions and a-recoil nuclei in a given material? (2) Is the dose-dependence of the accumulated damage similar? The purpose of this investigation was to assess the extent of these similarities in selected materials. We utilized transmission electron microscopy (TEM) to characterize the radiation damage and measure its dose-dependence.

scholarly journals Reliability and Fatigue Analysis in Cantilever-Based MEMS Devices Operating in Harsh Environments

2014 ◽  
Vol 2014 ◽  
pp. 1-16 ◽  
Author(s):  
Mohammad Tariq Jan ◽  
Nor Hisham Bin Hamid ◽  
Mohd Haris Md Khir ◽  
Khalid Ashraf ◽  
Mohammad Shoaib
Keyword(s):  
Structural Damage ◽  
Focal Point ◽  
Operating Conditions ◽  
Harsh Environments ◽  
Mems Devices ◽  
Paris Law ◽  
Modern Engineering ◽  
Reliability Issue ◽  
High Level ◽  
Microfabrication Techniques

The microelectromechanical system (MEMS) is one of the most diversified fields of microelectronics; it is rated to be the most promising technology of modern engineering. MEMS can sense, actuate, and integrate mechanical and electromechanical components of micro- and nano sizes on a single silicon substrate using microfabrication techniques. MEMS industry is at the verge of transforming the semiconductor world into MEMS universe, apart from other hindrances; the reliability of these devices is the focal point of recent research. Commercialization is highly dependent on the reliability of these devices. MEMS requires a high level of reliability. Several technological factors, operating conditions, and environmental effects influencing the performances of MEMS devices must be completely understood. This study reviews some of the major reliability issues and failure mechanisms. Specifically, the fatigue in MEMS is a major material reliability issue resulting in structural damage, crack growth, and lifetime measurements of MEMS devices in the light of statistical distribution and fatigue implementation of Paris' law for fatigue crack accumulation under the influence of undesirable operating and environmental conditions.

scholarly journals Dolomite and Micronutrient Fertilizer Affect Phosphorus Fate When Growing Crape Myrtle in Pine Bark

HortScience ◽  
2020 ◽  
Vol 55 (6) ◽  
pp. 832-840 ◽  
Author(s):  
Jacob H. Shreckhise ◽  
James S. Owen ◽  
Matthew J. Eick ◽  
Alexander X. Niemiera ◽  
James E. Altland ◽  
...  
Keyword(s):  
Pore Water ◽  
Crop Production ◽  
Management Practice ◽  
Dry Weight ◽  
P Uptake ◽  
Pine Bark ◽  
Uptake Efficiency ◽  
Chemical Conditions ◽  
Micronutrient Fertilizer ◽  
Water Extractable

Soilless substrates are routinely amended with dolomite and sulfate-based micronutrients to improve fertility, but the effect of these amendments on phosphorous (P) in substrate pore-water during containerized crop production is poorly understood. The objectives of this research were as follows: compare the effects of dolomite and sulfate-based micronutrient amendments on total P (TP), total dissolved P (TDP), orthophosphate P (OP), and particulate P (PP; TP − TDP) concentrations in pour-through extracts; to model saturated solid phases in substrate pore-water using Visual MINTEQ; and to assess the effects of dolomite and micronutrient amendments on growth and subsequent P uptake efficiency (PUE) of Lagerstroemia L. ‘Natchez’ (crape myrtle) potted in pine bark. Containerized crape myrtle were grown in a greenhouse for 93 days in a 100% pine bark substrate containing a polymer-coated 19N–2.6P–10.8K controlled-release fertilizer (CRF) and one of four substrate amendment treatments: no dolomite or micronutrients (control), 2.97 kg·m−3 dolomite (FL); 0.89 kg·m−3 micronutrients (FM); or both dolomite and micronutrients (FLM). Pour-through extracts were collected approximately weekly and fractioned to measure pore-water TP, TDP, and OP and to calculate PP. Particulate P concentrations in pour-through extracts were generally unaffected by amendments. Relative to the control, amending pine bark with FLM reduced water-extractable OP, TDP, and TP concentrations by ≈56%, had no effect on P uptake efficiency, and resulted in 34% higher total dry weight (TDW) of crape myrtle. The FM substrate had effects similar to those of FLM on plant TDW and PUE, and FM reduced pore-water OP, TDP, and TP concentrations by 32% to 36% compared with the control. Crape myrtle grown in FL had 28% lower TDW but pour-through OP, TDP, and TP concentrations were similar to those of the control. Chemical conditions in FLM were favorable for precipitation of manganese hydrogen phosphate (MnHPO4), which may have contributed to lower water-extractable P concentrations in this treatment. This research suggests that amending pine bark substrate with dolomite and a sulfate-based micronutrient fertilizer should be considered a best management practice for nursery crop production.

Venting Manhole Cover: A Nonlinear Spring-Mass System

2020 ◽  
Author(s):  
Arris S. Tijsseling ◽  
Jose G. Vasconcelos ◽  
Qingzhi Hou ◽  
Zafer Bozkuş
Keyword(s):  
Simple Model ◽  
Dynamic Behavior ◽  
Structural Damage ◽  
Heavy Rainfall ◽  
Road Traffic ◽  
Mass System ◽  
Strongly Nonlinear ◽  
Dangerous Situation ◽  
High Level ◽  
Air Column

Abstract Manholes are vertical shafts connecting underground sewers with street-level terminals. They are covered by heavy lids. During periods of heavy rainfall, the air column in the upper part of the manhole may be compressed to such high level that the lid moves up. Of course, this is a dangerous situation for pedestrians and road traffic. Bolting the lid may provide a solution to the problem, but it is known that air pressurization underneath can result in structural damage. A simple model is proposed to describe the lifting of the lid (manhole cover). When the lid moves up, air is allowed to escape so that the lifting pressure decreases and the lid moves down, whereupon the air pressure increases again. This repetition might lead to the realistic phenomenon of the dancing manhole cover. Since the model is strongly nonlinear, interesting dynamic behavior is expected.

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